In an image pickup apparatus employing an image pickup device such as a CMOS image sensor, fixed pattern noise occurs which is caused by a readout circuit in the image pickup device. One commonly known method for reducing such fixed pattern noise so as to obtain a high-quality image is a method in which fixed pattern noise is corrected by subtracting prestored data from image data. For example, in PTL 1, a method is disclosed in which fixed pattern noise in an image may be corrected by using prestored one-dimensional data in accordance with the image pickup conditions.